1. Field of the Invention
The present invention relates to a thin-film transistor (TFT) array substrate and a liquid crystal display device having the TFT array substrate. More particularly, the present invention relates to a TFT array substrate capable of reducing power consumption, and a liquid crystal display device having the TFT array substrate
2. Description of the Related Art
In general, a liquid crystal display (LCD) device includes two substrates having electrodes, respectively, and a liquid crystal layer disposed between the two substrates. The liquid crystal layer has dielectric anisotropy. When a voltage is applied to the electrodes, an electric field is generated between the electrodes. By controlling the electric fields, an optical transmittance of the liquid crystal layer is adjusted to display an image.
The LCD device displays an image by using ambient light or artificial light. When the LCD device uses artificial light, the LCD device employs a backlight assembly for generating the artificial light. The backlight assembly typically employs a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), or a light-emitting diode (LED), etc. as a light source. Power consumption by the backlight assembly comprises most of power consumption of the LCD device. Therefore, when the efficiency of the backlight assembly is increased or the usage time is reduced, power consumption is reduced. In particular, a mobile device such as a cellular phone may use a battery as a power source, so that the available electric power may be limited. Therefore, there remains a need in the art for a mobile device capable of operation with reduced power consumption.